66 research outputs found
Weeds in the treated field - a realistic scenario for pollinator risk assessment?
In July 2013 the European Food Safety Authority (EFSA) released its final guidance on the risk assessment of plant protection products (PPPs) to bees1. One objective of the guidance was to produce a simple and cost effective first tier risk assessment scheme to ensure that the appropriate level of protection is achieved. However, recent impact analyses have indicated that the first tier of this risk assessment does not act effectively as a screen for compounds of low risk to bees. For example substances showing no toxicity to bees often fail the tier 1 risk assessment based on a worst-case exposure to flowering weeds inside the treated field. If realistic farming practices (e.g. tillage and herbicide applications) are considered, weeds are not usually prevalent in arable fields. It is therefore suggested that the scenarios in the guidance could be considered overly conservative and in some instances unrealistic. The EFSA guidance states that if <10% of the area of use is flowering weeds then the exposure route is not relevant in the 90th %ile case, and thus does not need to be considered. However, despite this, the option to generate data or refine assessments based on available data is questioned as no guidance for the assessment of the abundance of weeds is available. As part of an industry-led initiative we present and discuss the use of empirical evidence (i.e. occurrence and growth stage of weeds in control plots from herbicide efficacy field trials conducted for regulatory submission) to illustrate that the scenarios in the guidance document could be modified using currently available data to create a more effective tier 1 risk assessment and still ensure that the appropriate level of protection is achieved. We have demonstrated here that less than 2% of all weeds recorded in arable crop trials (represented here by wheat, oilseed rape, sugar beet, sunflower, potatoes, maize, peas and beans) are at a flowering growth stage; therefore in arable crops the flowering weeds scenario is not applicable for the 90th %ile exposure. For permanent crop trials (represented here by orchards and vines) 37% of weeds were recorded at a flowering growth stage. When the attractiveness and density data are considered, the percentage of attractive, flowering weeds which cover >10% of the ground area is only 12.3%, indicating that for permanent crops further investigation may be required as to whether this scenario is relevant
Introgression in the genus Campylobacter: generation and spread of mosaic alleles
Horizontal genetic exchange strongly influences the evolution of many bacteria, substantially contributing to difficulties in defining their position in taxonomic groups. In particular, how clusters of related bacterial genotypes – currently classified as microbiological species – evolve and are maintained remains controversial. The nature and magnitude of gene exchange between two closely related (approx. 15 % nucleotide divergence) microbiologically defined species, Campylobacter jejuni and Campylobacter coli, was investigated by the examination of mosaic alleles, those with some ancestry from each population. A total of 1738 alleles from 2953 seven-locus housekeeping gene sequence types (STs) were probabilistically assigned to each species group with the model-based clustering algorithm structure. Alleles with less than 75 % assignment probability to one of the populations were confirmed as mosaics using the structure linkage model. For each of these, the putative source of the recombinant region was determined and the allele was mapped onto a clonalframe genealogy derived from concatenated ST sequences. This enabled the direction and frequency of introgression between the two populations to be established, with 8.3 % of C. coli clade 1 alleles having acquired C. jejuni sequence, compared to 0.5 % for the reciprocal process. Once generated, mosaic genes spread within C. coli clade 1 by a combination of clonal expansion and lateral gene transfer, with some evidence of erosion of the mosaics by reacquisition of C. coli sequence. These observations confirm previous analyses of the exchange of complete housekeeping alleles and extend this work by describing the processes of horizontal gene transfer and subsequent spread within recipient species
Comparison of Francisella tularensis genomes reveals evolutionary events associated with the emergence of human pathogenic strains
.Sequencing of the non-pathogenic Francisella tularensis sub-species novicida U112, and comparison with two pathogenic sub-species, provides insights into the evolution of pathogenicity in these species
"Liberalizing" the English National Health Service: background and risks to healthcare entitlement
Resumo: A recente reforma do Serviço Nacional de Saúde (NHS) inglês por meio do Health and Social Care Act de 2012 introduziu mudanças importantes na organização, gestão e prestação de serviços públicos de saúde na Inglaterra. O objetivo deste estudo é analisar as reformas do NHS no contexto histórico de predomínio de teorias neoliberais desde 1980 e discutir o processo de "liberalização" do NHS. São identificados e analisados três momentos: (i) gradativa substituição ideológica e teórica (1979-1990) - transição da lógica profissional e sanitária para uma lógica gerencial/comercial; (ii) burocracia e mercado incipiente (1991-2004) - estruturação de burocracia voltada à administração do mercado interno e expansão de medidas pró-mercado; e (iii) abertura ao mercado, fragmentação e descontinuidade de serviços (2005-2012) - fragilização do modelo de saúde territorial e consolidação da saúde como um mercado aberto a prestadores públicos e privados. Esse processo gradual e constante de liberalização vem levando ao fechamento de serviços e à restrição do acesso, comprometendo a integralidade, a equidade e o direito universal à saúde no NHS
New Insights into the Evolution of Wolbachia Infections in Filarial Nematodes Inferred from a Large Range of Screened Species
Wolbachia are intriguing symbiotic endobacteria with a peculiar host range that includes arthropods and a single nematode family, the Onchocercidae encompassing agents of filariases. This raises the question of the origin of infection in filariae. Wolbachia infect the female germline and the hypodermis. Some evidences lead to the theory that Wolbachia act as mutualist and coevolved with filariae from one infection event: their removal sterilizes female filariae; all the specimens of a positive species are infected; Wolbachia are vertically inherited; a few species lost the symbiont. However, most data on Wolbachia and filaria relationships derive from studies on few species of Onchocercinae and Dirofilariinae, from mammals.We investigated the Wolbachia distribution testing 35 filarial species, including 28 species and 7 genera and/or subgenera newly screened, using PCR, immunohistochemical staining, whole mount fluorescent analysis, and cocladogenesis analysis. (i) Among the newly screened Onchocercinae from mammals eight species harbour Wolbachia but for some of them, bacteria are absent in the hypodermis, or in variable density. (ii) Wolbachia are not detected in the pathological model Monanema martini and in 8, upon 9, species of Cercopithifilaria. (iii) Supergroup F Wolbachia is identified in two newly screened Mansonella species and in Cercopithifilaria japonica. (iv) Type F Wolbachia infect the intestinal cells and somatic female genital tract. (v) Among Oswaldofilariinae, Waltonellinae and Splendidofilariinae, from saurian, anuran and bird respectively, Wolbachia are not detected.The absence of Wolbachia in 63% of onchocercids, notably in the ancestral Oswaldofilariinae estimated 140 mya old, the diverse tissues or specimens distribution, and a recent lateral transfer in supergroup F Wolbachia, modify the current view on the role and evolution of the endosymbiont and their hosts. Further genomic analyses on some of the newly sampled species are welcomed to decipher the open questions
Prognostic model to predict postoperative acute kidney injury in patients undergoing major gastrointestinal surgery based on a national prospective observational cohort study.
Background: Acute illness, existing co-morbidities and surgical stress response can all contribute to postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery. The aim of this study was prospectively to develop a pragmatic prognostic model to stratify patients according to risk of developing AKI after major gastrointestinal surgery. Methods: This prospective multicentre cohort study included consecutive adults undergoing elective or emergency gastrointestinal resection, liver resection or stoma reversal in 2-week blocks over a continuous 3-month period. The primary outcome was the rate of AKI within 7 days of surgery. Bootstrap stability was used to select clinically plausible risk factors into the model. Internal model validation was carried out by bootstrap validation. Results: A total of 4544 patients were included across 173 centres in the UK and Ireland. The overall rate of AKI was 14·2 per cent (646 of 4544) and the 30-day mortality rate was 1·8 per cent (84 of 4544). Stage 1 AKI was significantly associated with 30-day mortality (unadjusted odds ratio 7·61, 95 per cent c.i. 4·49 to 12·90; P < 0·001), with increasing odds of death with each AKI stage. Six variables were selected for inclusion in the prognostic model: age, sex, ASA grade, preoperative estimated glomerular filtration rate, planned open surgery and preoperative use of either an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker. Internal validation demonstrated good model discrimination (c-statistic 0·65). Discussion: Following major gastrointestinal surgery, AKI occurred in one in seven patients. This preoperative prognostic model identified patients at high risk of postoperative AKI. Validation in an independent data set is required to ensure generalizability
Imaging biomarker roadmap for cancer studies.
Imaging biomarkers (IBs) are integral to the routine management of patients with cancer. IBs used daily in oncology include clinical TNM stage, objective response and left ventricular ejection fraction. Other CT, MRI, PET and ultrasonography biomarkers are used extensively in cancer research and drug development. New IBs need to be established either as useful tools for testing research hypotheses in clinical trials and research studies, or as clinical decision-making tools for use in healthcare, by crossing 'translational gaps' through validation and qualification. Important differences exist between IBs and biospecimen-derived biomarkers and, therefore, the development of IBs requires a tailored 'roadmap'. Recognizing this need, Cancer Research UK (CRUK) and the European Organisation for Research and Treatment of Cancer (EORTC) assembled experts to review, debate and summarize the challenges of IB validation and qualification. This consensus group has produced 14 key recommendations for accelerating the clinical translation of IBs, which highlight the role of parallel (rather than sequential) tracks of technical (assay) validation, biological/clinical validation and assessment of cost-effectiveness; the need for IB standardization and accreditation systems; the need to continually revisit IB precision; an alternative framework for biological/clinical validation of IBs; and the essential requirements for multicentre studies to qualify IBs for clinical use.Development of this roadmap received support from Cancer Research UK and the Engineering and Physical Sciences Research Council (grant references A/15267, A/16463, A/16464, A/16465, A/16466 and A/18097), the EORTC Cancer Research Fund, and the Innovative Medicines Initiative Joint Undertaking (grant agreement number 115151), resources of which are composed of financial contribution from the European Union's Seventh Framework Programme (FP7/2007-2013) and European Federation of Pharmaceutical Industries and Associations (EFPIA) companies' in kind contribution
Recommended from our members
Los Alamos National Laboratory Report LA-1839 (Del.)
A spectrophotometric method used in the determination of thorium was modified for the purpose of analyzing plutonium alloys which contained 0.01 to 0.8 percent thorium. Absorbance values were measured at 545 millimicrons for solutions containing thorium and thorin, the organic reagent added to form a colored complex with thorium in the presence of plutonium (III) . With plutonium-thorium 0.8 percent thorium, the average recovery of thorium was 99.6 +- 1.5 percent. For similar samples containing 0.01 to 0.2 percent thorium, the average recovery 101.0 +- 3.4 percent, after the thorium was separated from plutonium by precipitation of thorium fluoride with the aid of lanthanum fluoride as a carrier
- …